Method and apparatus for diecasting including a flash cavity

ABSTRACT

The present invention is a diecasting method and apparatus. The apparatus includes a dieholder having an opening defined in one surface. A recess portion is provided in the sidewall of the dieholder opening. A die block is removably positioned in the dieholder opening. The die block surface is complementary with the sidewall recess portion for forming a flash stop. In one embodiment, the dieholder defines a shoulder and the die block has a complementary flange. In another embodiment, the die block and dieholder define complementary openings which receive a separable flash stop member. In both embodiments, a flash groove or chamber is located adjacent the flash stop and is in communication with the die casting cavity. The flash chamber is in liquid communication with the die cavity. When molten metal solidifies it forms an integral casting having flash thereon of a predetermined configuration.

United States Patent 3,387,646 6/1968 Lauth 164/120 Primary Examiner-J.Spencer Overholser Assistant Examiner-John E. Roethel At1omey--Owen andOwen The 55625? inventio rTis a diecasting method and apparatus. Theapparatus includes a dieholder having an opening defined in one surface.A recess portion is provided in the sidewall of the dieholder opening. Adie block is removably positioned in the dieholder opening. The dieblock surface is complementary with the sidewall recess portion forforming a flash stop. in one embodiment, the dieholder defines ashoulder and the die block has a complementary flange. In anotherembodiment, the die block and dieholder define complementary openingswhich receive a separable flash stop member. in both embodiments, aflash groove or chamber is located adjacent the flash stop and is incommunication with the die casting cavity. The flash chamber is inliquid communication with the die cavity. When molten metal solidifiesit forms an integral casting having flash thereon of a predeterminedconfiguration.

PATENTEU GET 1 2 WI 6 l 2, l 53 FEE-E 'NVENTOR:

fiYRmI Y K011i METHOD AND APPARATUS FOR DIECASTING INCLUDING A FLASHCAVITY BACKGROUND OF THE INVENTION This invention relates generally todiecasting. In a diecasting operation, when molten metal under highdiecasting pressures flows across joints, for examples, the jointsformed between dieholdeis and impression dies or dieholders and gateinserts, flash often forms in the joints. This situation is aggravatedwhen the dieholder members and the die blocks are constructed ofmaterials having different coefficients of thermal expansion, forexample, where the dieholder member is constructed of steel and the dieblock is constructed of a refractory material or a refractory metal.

Even where the dieholders and impression dies are constructed ofmaterials haviqgthe same or similar coefiicients of thermal expansion,flash forms in the joints or die seals because of the differentialtemperature conditions which exist.

In prior art apparatus, the flash which formed in the joints or crevicesduring a diecasting operation reduced the production life of the die. Ifflash remains in the joints, cast overs are formed in subsequentdiecastings. The present invention is particularly useful in FerrousDiecasting where pouring temperatures of 2,800 F. and casting pressuresof 4,000 p.s.i. are not unusual.

SUMMARY OF THE INVENTION The present invention relates to a diecastingmethod and to diecasting apparatus having preformed flash chambersdefined at the critical mating joints between the various diecomponents. A flash stop is provided at the lower end of the flashchamber. A diecasting formed in diecasting apparatus, according to thepresent invention, has flash of a predetermined size which can easily beremoved on a uniform production basis. In addition, the presentinvention provides diecasting apparatus which is suitable for use in asustained production situation.

More specifically, the diecasting apparatus according to the presentinvention includes a dieholder member having an opening defined in onesurface. The opening includes a sidewall which has a recess portionspaced from the surface of the dieholder member. A removable die blockis positioned in the dieholder member opening and includes meanscomplementary with the sidewall recess portion for forming a flash stop.In one embodiment, the sidewall recess portion comprises a shoulder andthe die block means comprises a flange which is complementary with theshoulder. When the flange abuts the shoulder, it forms a flash stop. Aflash groove or flash chamber is defined by the dieholder member and thedie block, and is located adjacent the flash stop. The flash chamber isof a predetermined configuration and is in communication with thecasting cavity.

In another embodiment, the sidewall recess portion of the dieholdermember comprises a groove and the die block includes a surfacecomplementary with the groove. The complementary surface and the groovereceive a flash stop member. Again, in this embodiment, the sidewall ofthe dieholder member and the die block define a flash chamber adjacentthe flash stop.

In the present method, the flash chambers of either embodiment are inliquid communication with the die cavity. When molten metal enters theflash chambers, the flash stops impede its flow. When the molten metalsolidifies it forms an integral casting having flash thereon ofpredetermined configurations.

It is an object of the present invention to provide an improveddiecasting method.

It is an object of the present invention to provide improved diecastingapparatus and more particularly a diecasting apparatus which has a flashchamber of a predetermined size.

Another object of the present invention is to provide Other objects andadvantages of the present invention will become apparent from thefollowing detailed description, reference being made to the accompanyingdrawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary, partiallysectional and partially diagrammatic view of one embodiment ofdiecasting apparatus constructed according to the present invention;

FIG. 2 is a fragmentary sectional view of another embodiment ofdiecasting apparatus constructed according to the present invention;

FIG. 3 is a view taken along the line 3-3 of FIG. 1 and shown on anenlarged scale; and

FIG. 4 is a partially sectional view taken along the line 4-4 of FIG. 1and shown on a slightly enlarged scale.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a portionof a typical diecasting machine is shown. In a conventional manner, thediecasting machine includes a sliding platen l0 and a front platen 11.The sliding platen 10 is mounted for movement on horizontal machine bars12. An ejector die holding block 13 is attached to the sliding platen 10and cooperates with a stationary cover die holding block 14 which isattached to the front platen 11. The ejector die holding block 13 has agenerally planar surface 15 which abuts a similar surface 16 of thecover die holding block 14, when the machine is in the casting positionshown in FIG. 1.

Each of the die holding members or blocks 13 and 14 have openingsdefined in their surfaces 15 and 16. The exact number of openings is, ofcourse, determined by the particular die design required for aparticular casting. In the design shown in FIG. 1, an opening 17 havinga sidewall 18 and a bottom 19 is defined in the surface 15 of theholding block 13. Opposed and cooperating openings 20 and 21 are definedin the ejector die holding block 13 and the cover die holding block 14respectively. The opening 20 has a bottom 22 and a sidewall 23.Similarly, the opening 21 has a bottom 24 and a sidewall 25.

In the FIG. 1 embodiment, another opening 26 is defined in the cover dieholding block 14. The opening 26 has a bottom 27 and a sidewall 28. Asseen in FIG. 1, the openings 21 and 26 overlap at one point.

The opening 17 in the ejector die holding block 13 has a recess portioncomprising a semicircular groove 30 which is spaced from and has a majoraxis which is generally parallel to the planar surface 15. The opening17 removably receives a die impression block 31 having a casting surface32 and a body portion 33. The body portion 33 is inserted in the opening17. The die block 31 includes a curved surface portion 34 which isopposed to and complementary with the semicircular groove 30. A flashrod 35 is received by the semicircular groove 30 and the curved surfaceportion 34. A generally V- shaped groove or flash chamber 36 extendsbetween the flash rod 35 and the surface 15 and is defined by taperedsurface portions of the sidewall 18 and the die block 31. In the presentembodiment, the flash rod 35 is arcuate in configuration and isrelatively short. The ejector die block 13 and the die block 31 includeconventional ejector pins 37 (see FIGS; I and 4).

Referring to FIGS. 1 and 4, a second semicircular groove 30a is formedin the sidewall 18 of the holding block 13. The groove 30a and a secondcurved surface portion 34a of the die block 31 receive a flash rod 35a.Tapered portions of the sidewall 18 and the outer surface of the dieblock 31 define a V-shaped groove or flash chamber 36a.

The opening 26 in the holding block 14 receives a cover die impressionblock 38 having a casting surface 39 and an outer sidewall surface 40.When in the casting position shown in FIG. I, the casting surfaces 32and 39 of the die blocks 31 and 38 define a casting cavity 41. It willbe noted that the V- shaped grooves or flash chambers 36 and 36a are incommunication with the casting cavity 41.

The openings and 21 defined in the holding blocks 13 and 14 receivemating gate blocks 42 and 43 which in the present specification are alsotermed die blocks. The gate blocks 42 and 43 define a gate runner 44which is in communication with a conventional plunger sleeve assembly45.

Referring to FIGS. 1 and 3, a pair of flash rods 46 and 47 extendthrough the holding blocks 13 and 14. The flash rod 46 is received by asemicircular opening 48 defined in the sidewall 23 of the opening 20 anda cooperating semicircular opening 49 defined in the adjoining surfaceof the gate block 43. A generally V-notch groove or flash chamber 50extends above the flash rod 46 and is defined by the sidewall 23 of theopening 20 and the adjoining surface of the gate block 43.

In a similar manner, the flash rod 47 is received by a semicircularopening 52 defined in the surface of the gate block 42 and acomplementary surface portion 53 of the sidewall 40 of the cover dieblock 38. A V-notch groove or flash chamber 54 extends from the flashrod 47 to the surface of the cover die block 38.

The present invention is particularly adaptable to a situation where,for example, the holding blocks 13 and 14 are constructed of steel andthe die blocks 31, 38 and 43 are constructed of a refractory material,for example, a refractory metal such as a molybdenum refractory. Becauseof the high pressures involved in diecasting, sometimes in theneighborhood of 10,000 psi. when diecasting aluminum, molten metalforces its way into the joints between abutting components. In prior artdiecasting apparatus, the joints tend to widen and the resulting flashwas nonuniform. Flash sometimes remained with the die blocks rather thanbeing ejected with the casting. When this occurred, cast overs wereformed in subsequent castings. By utilizing the diecasting apparatusaccording to the invention, the molten metal is forced into preformedflash chambers, for examples, the V-notch grooves or flash chambers 36,36a, 50 and 54. As the molten metal travels inwardly into the respectiveflash chambers, it encounters the flash stops, for examples, the flashrods 35, 35a, 46 and 47. An important feature of the present inventionis that the flash formed in the respective flash chambers is ejectedwith each casting, thus minimizing cast over defects.

In the present embodiment, the flash rods 35, 35a, 46 and 47 aremetallic rods which stop the travel of the molten metal because of theirheat sink properties and also because they form physical barriers to thefurther travel of the molten metal. Eutectic rods may also be utilizedas flash rods. Furthermore, the flash rods 35, 35a, 46 and 47 may haveother geometrical configurations. It has been found that when the flashrods extend through the die blocks, for example, in the manner that theflash rods 46 and 47 extend through the holding blocks 13 and 14, thatthe flash rods may be tubular and a cooling fluid circulatedtherethrough.

The casting and its attached flash is removed by the conventionalejector pins 37 in a direction away from the apexes of the wedge-shapedflash chambers 36, 36a, 50 and 54. As is well known in the art and shownin U.S. Pat. No. 3,106,002, the die block 31 remains stationary in theopening 17 of the ejector die block 13 as the casting is ejected.

The flash which is formed in the flash chambers 36, 36a, 50 and 54 maybe easily removed from a diecasting after it is ejected from thediecasting machine. The flash which is formed is unifonn and may beremoved on a production basis. It has been found that when using thediecasting apparatus according to the present invention, which has theflash chambers, that the die life is longer, sustained diecastingproduction may be achieved, and cast over defects are substantiallyeliminated.

Another embodiment of the present invention is shown in FIG. 2. In thisembodiment, a dieholder member 58 has an upper planar surface 59. Anopening 60 is defined in the surface 59 and has a sidewall 61 and abottom 62. A die block 63 is removably received in the opening 60. Thesidewall 61 of the die holder member 58 includes a sidewall recessportion or shoulder 64. The die block 63 includes a flange 65 which iscomplementary with the shoulder 64. The flange 65 and the shoulder 64form a flash stop when the die block 63 is inserted in the opening 60 ofthe dieholder member 58, as shown in FIG. 2.

Immediately above the shoulder 64 and the flange 65, a portion of thesidewall 61 and a portion of the side of the die block 63 define agenerally V-notch groove or flash chamber 66. When the molten metal,illustrated by the reference number 67 in FIG. 2, is forced into the diecavity, it enters the flash chamber 66, solidifies, and forms a flashprojection 68. The flash stop formed by the shoulder 64 and the change65 retards the movement of molten metal 67.

After a diecasting is removed from the diecasting machine, the flashprojection 68 is removed.

What 1 claim is:

1. Apparatus for diecasting, wherein a dieholder member has an openingdefined in one surface, said opening having a sidewall, said sidewallhaving a recess portion spaced from such surface of such dieholdermember, such recess portion comprising a groove of a predeterminedconfiguration, said apparatus comprising a die block insertable in suchopening of such dieholder member, said die block having a castingsurface and means on said die block complementary with such sidewallrecess portion for forming a flash stop, said forming means including acomplementary surface portion on said die block and a rod having amating configuration positioned between said groove and saidcomplementary surface portion, and wherein a portion of the surface ofsaid die block and a portion of such sidewall of such dieholder memberdefine a flash chamber, said flash chamber extending from said flashstop toward such surface.

2. Apparatus for diecasting, wherein a dieholder member has an openingdefined in one surface, said opening having a sidewall, said sidewallhaving a recess portion spaced from such surface of such dieholdermember, said apparatus comprising a die block insertable in such openingof such die holder member, said die block having a casting surface andmeans on said die block complementary with such sidewall recess portionfor forming a flash stop, a portion of a surface on said die block and aportion of such sidewall of such die holder member defining a flashchamber, said flash chamber extending from said flash stop toward suchsurface, said flash chamber being generally wedge shaped in crosssection, wherein said flash chamber flares outwardly from said flashstop, and means for removing the casting in a direction away from theapex of the wedge-shaped flash chamber without separating said die blockfrom said opening.

3. Apparatus according to claim 1, wherein such recess portion of suchdieholder member sidewall defines a shoulder and said means on said dieimpression block comprises a flange complementary with such shoulder,said flange and such shoulder forming said flash stop, whereby saidflash stop retards the movement of molten metal from said flash chamber.

4. Apparatus according to claim 1, wherein such groove is semicircularand said rod has a generally circular cross section.

5. A method of forming flash of a predetermined configuration on adiecasting to eliminate cast over defects in subsequent diecastings,wherein joints are defined between adjacent die parts, which arestationary during the casting operations, including providing awedge-shaped flash chamber between said adjacent die parts, said flashchamber being in liquid communication with the die cavity, providing aflash stop in the flash chamber to impede the flow of molten metal,filling the die cavity and the flash chamber with molten metal,solidifying the molten metal within the die cavity and the flash chamberto form an integral casting having flash thereon of the predeterminedconfiguration and removing the casting from the die parts, the castingbeing removed in a direction away from the apex of the wedge-shapedflash chamber.

6. Apparatus for diecasting comprising, in combination, a dieholdermember having a die opening defined in one surface, said die openinghaving a sidewall and a bottom, said 8. Apparatus according to claim 6,wherein said receiving groove has a semicircular cross section andwherein said flash member is a circular rod.

9. Apparatus for diecasting comprising, in combination, a dieholdermember having a die opening defined in one surface, said die openinghaving a sidewall and a bottom, said sidewall defining a shoulder spacedfrom said surface, a die block removably mounted in said die opening, aflange on said die block engageable with said shoulder, said shoulderand said flange forming a flash stop, a flash chamber extending betweensaid shoulder and said die opening surface defined by said dieholder andsaid die block, said flash chamber being generally wedge shaped in crosssection, flaring outwardly from said flash stop, and means for removingthe casting in a direction away from the apex of the wedge-shaped flashchamber without removing said die block from said die open- 10.Apparatus accbrding to claim 9, wherein said dieholder is constructed ofsteel and wherein said die block is constructed of a refractory metal.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 r512 r 153 Dated October 12 1971 Inventor) Byron W. Koch It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 4, line 11, the word "change" should read flange and line 49,(claim 3) "claim 1" should read claim 2 Signed and sealed this ll th dayof March 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

1. Apparatus for diecasting, wherein a dieholder member has an openingdefined in one surface, said opening having a sidewall, said sidewallhaving a recess portion spaced from such surface of such dieholdermember, such recess portion comprising a groove of a predeterminedconfiguration, said apparatus comprising a die block insertable in suchopening of such dieholder member, said die block having a castingsurface and means on said die block complementary with such sidewallrecess portion for forming a flash stop, said forming means including acomplementary surface portion on said die block and a rod having amating configuration positioned between said groove and saidcomplementary surface portion, and wherein a portion of the surface ofsaid die block and a portion of such sidewall of such dieholder memberdefine a flash chamber, said flash chamber extending from said flashstop toward such surface.
 2. Apparatus for diecasting, wherein adieholder member has an opening defined in one surface, said openinghaving a sidewall, said sidewall having a recess portion spaced fromsuch surface of such dieholder member, said apparatus comprising a dieblock insertable in such opening of such die holder member, said dieblock having a casting surface and means on said die block complementarywith such sidewall recess portion for forming a flash stop, a portion ofa surface on said die block and a portion of such sidewall of such dieholder member defining a flash chamber, said flash chamber extendingfrom said flash stop toward such surface, said flash chamber beinggenerally wedge shaPed in cross section, wherein said flash chamberflares outwardly from said flash stop, and means for removing thecasting in a direction away from the apex of the wedge-shaped flashchamber without separating said die block from said opening. 3.Apparatus according to claim 1, wherein such recess portion of suchdieholder member sidewall defines a shoulder and said means on said dieimpression block comprises a flange complementary with such shoulder,said flange and such shoulder forming said flash stop, whereby saidflash stop retards the movement of molten metal from said flash chamber.4. Apparatus according to claim 1, wherein such groove is semicircularand said rod has a generally circular cross section.
 5. A method offorming flash of a predetermined configuration on a diecasting toeliminate cast over defects in subsequent diecastings, wherein jointsare defined between adjacent die parts, which are stationary during thecasting operations, including providing a wedge-shaped flash chamberbetween said adjacent die parts, said flash chamber being in liquidcommunication with the die cavity, providing a flash stop in the flashchamber to impede the flow of molten metal, filling the die cavity andthe flash chamber with molten metal, solidifying the molten metal withinthe die cavity and the flash chamber to form an integral casting havingflash thereon of the predetermined configuration and removing thecasting from the die parts, the casting being removed in a directionaway from the apex of the wedge-shaped flash chamber.
 6. Apparatus fordiecasting comprising, in combination, a dieholder member having a dieopening defined in one surface, said die opening having a sidewall and abottom, said sidewall defining a receiving groove, a die block removablymounted in said die opening, said die block having a surfacecomplementary with said receiving groove, a separable flash memberpositioned in said groove and engaging said complementary surface ofsaid die block, and a flash chamber defined by said dieholder member andsaid die block adjacent said flash member.
 7. Apparatus according toclaim 6, wherein said dieholder is constructed of steel and wherein saiddie block is constructed of a refractory material.
 8. Apparatusaccording to claim 6, wherein said receiving groove has a semicircularcross section and wherein said flash member is a circular rod. 9.Apparatus for diecasting comprising, in combination, a dieholder memberhaving a die opening defined in one surface, said die opening having asidewall and a bottom, said sidewall defining a shoulder spaced fromsaid surface, a die block removably mounted in said die opening, aflange on said die block engageable with said shoulder, said shoulderand said flange forming a flash stop, a flash chamber extending betweensaid shoulder and said die opening surface defined by said dieholder andsaid die block, said flash chamber being generally wedge shaped in crosssection, flaring outwardly from said flash stop, and means for removingthe casting in a direction away from the apex of the wedge-shaped flashchamber without removing said die block from said die opening. 10.Apparatus according to claim 9, wherein said dieholder is constructed ofsteel and wherein said die block is constructed of a refractory metal.